Aldol condensation of acetone in the two-phase system solid base-benzene in the presence of benzyltriethylammonium chloride

Abstract

1. We propose a mechanism for the aldol condensation of acetone in the presence of solid base, explaining the optimum way of forming diacetone alcohol by filling the surface of the base with the diacetone alcohol and acetone anions. 2. Disappearance of the diacetone alcohol from the reaction products after filling the principal centers of the free base was caused by its decomposition under the influence of the acetone anion in the organic phase. 3. The reaction orders for acetone in formation of mesityl oxide and phorone in the presence of solid NaOH are second and third, respectively. 4. We have studied the aldol condensation of acetone in the presence of solid NaOH and benzyltriethylammonium chloride. The formation of diacetone alcohol proceeds in the organic phase as a result of the interaction of the onium alcoholate of diacetone alcohol with acetone, which greatly speeds up the reaction rate. The second order of the reaction with respect to acetone is caused by the limiting step of desorption of the anion of diacetone alcohol inside the organic phase. 5 The role of the benzyldiethylammonium chloride consists of desorption from the surface of the base of the anions of acetone and diacetone alcohol adsorbed on it in the form of ionic pairs, leading to a reduction of the basic properties of the surface of the base.